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Everything I know about SSDs (2019)

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Re: Everything I know about SSDs (2019)

#5

Post by jmbwell »

I always thought 'flash' was a holdover from early reprogrammable ROM technology, non-volatile memory that you could erase by literally flashing a literal flashbulb over a little window on the chip. I would've sworn in a court of law that I recall this being called "flashable" memory, that erasing it was called "flashing" it, and reprogramming it in general was called "reflashing" in a sort of synecdoche. And I'd have assumed that this was the fundamental origin of what became _electronically_ erasable ROM (EEPROM), which led to all the various NVRAM technologies we have now, with "flashing" sticking as the term for reprogramming it, even after you could do it electronically.

It looks like the story these days is that someone at Toshiba thought up the name out of the blue. I'm skeptical!

Re: Everything I know about SSDs (2019)

#6

Post by thadt »

eatonphil wrote: post #4

You might also be interested in this AMA we held on r/databasedevelopment with two NVMe developers from Samsung. https://www.reddit.com/r/databasedevelopment/comments/1afpez...

Thanks for hosting (and posting it here). I was reading the "What Modern NVMe Storage Can Do..." paper just yesterday, and this was a great followup.

Re: Everything I know about SSDs (2019)

#8

Post by sgerenser »

jmbwell wrote: post #5

I always thought 'flash' was a holdover from early reprogrammable ROM technology, non-volatile memory that you could erase by literally flashing a literal flashbulb over a little window on the chip. I would've sworn in a court of law that I recall this being called "flashable" memory, that erasing it was called "flashing" it, and reprogramming it in general was called "reflashing" in a sort of synecdoche. And I'd hav…

I never heard of using a literal flash to reprogram EPROMs, but this wikipedia entry[1] makes your story for the origin of the term “Flashing” seem likely

EPROMs are easily recognizable by the transparent fused quartz (or on later models resin) window on the top of the package, through which the silicon chip is visible, and which permits exposure to ultraviolet light during erasing.

[1] https://en.m.wikipedia.org/wiki/EPROM

Re: Everything I know about SSDs (2019)

#9

Post by jmbwell »

sgerenser wrote: post #8
jmbwell wrote: post #5

I always thought 'flash' was a holdover from early reprogrammable ROM technology, non-volatile memory that you could erase by literally flashing a literal flashbulb over a little window on the chip. I would've sworn in a court of law that I recall this being called "flashable" memory, that erasing it was called "flashing" it, and reprogramming it in general was called "reflashing" in a sort of synecdoche. And I'd hav…

I never heard of using a literal flash to reprogram EPROMs, but this wikipedia entry[1] makes your story for the origin of the term “Flashing” seem likely EPROMs are easily recognizable by the transparent fused quartz (or on later models resin) window on the top of the package, through which the silicon chip is visible, and which permits exposure to ultraviolet light during erasing. [1] https://en.m.wikipedia.org/wik…

It does look like all the references I can find point to engineers at Toshiba in 1980 coining the name, although Google ngrams shows some references to "flash EPROM" prior to 1980, so I can't help but wonder if the idea existed at least in some form prior to 1980

Re: Everything I know about SSDs (2019)

#10

Post by caseyf »

password4321 wrote: post #7

I've heard SSDs are more likely to "fail fast". Can anyone recommended utilities that monitor and warn before SSD failures?

For NVMe, if you get the SMART data with smartmontools/smartctl, you can inspect Percentage Used.

"Percentage Used: Contains a vendor specific estimate of the percentage of life used for the Endurance Group based on the actual usage and the manufacturer’s prediction of NVM life. A value of 100 indicates that the estimated endurance of the NVM in the Endurance Group has been consumed, but may not indicate an NVM failure. The value is allowed to exceed 100."

for SATA/SAS SSDs, there is "Media_Wearout_Indicator" which hasn't been a particularly reliable indicator in my experience.

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